Strap tensioning tool



June l5, 1965 J. E. ATTAs STRAP TENsIoNING TooL 2 Sheets-Sheetv l FiledApr'.. 5, 1962 Fig- 3 J. E. ATTAS STRAP TENSIONING TOOL June 15, 1965 2Sheets-Sheet 2 Filed April 5. 1962 United States Patent O nlidl STRAPTENSNHNG TL .lach Eli Attas, Westmount, Quebec, Canada, assigner, bymesne assignments, to FMC Corporation, San Jose, tlalif., a corporationof Uelaware Filed Apr. 3, i962, Ser. No. 85,775 7 Claims. (Cl. Mil- 123)This invention relates to strapping tools of the type used fortensioning or stretching straps or bands about shipping carto-ns and thelike.

Cartons, bundles, packages and groups of articles to be shipped incommerce are frequently provided with reinforcing straps which extendtightly thereabout with the ends thereof held in overlapping relation bymeans of a suitable clamp. When all articles being strapped are of thesame size, strapping material precut to length is often used and whenstrapping articles of varying sizes, it is customary to withdraw theneeded length of strapping from a supply such as a roll and tension andsecure it about the article before cutting the secured portion from thesupply. In either event, the tensioning operation is generally performedwith the aid of a tool which has means for holding one end of thestrapping material stationary and means for engaging another portion ofthe strapping Ito draw it tight about the article in overlappingrelation with the held end whereby the overlapping portions may beengaged by a clamp or seal to hold the strapping tight. Such tools aregenerally known as tensioning tools or stretching tools and it is towardthe improvement of such tools that the present invention is directed.

lt is an object of this invention to provide a strap tensioning toolhaving an improved arrangement for holding one end of a length ofstrapping material stationary while the strapping is drawn tight aboutan article in overlapping relationship with the held end.

It is a more specic object of the invention Ito provide a straptensioning tool, of the type having a windlass about which the strap iswound to draw it tight, with a means which operates in conjunction withthe windlass to increase the grip on the stationary end of the strap asthe strap is drawn tighter by the windlass.

A. further object of the invention is to provide a strap tensioning toolof the windlass type wherein the windlass is operated by power andhaving a strap end gripping device which is released from the strap byoperation of a lever which is also effective to discontinue theapplication of power to the Windlass.

Another object of the invention is to provide a strap tensioning toolhaving gripping means for holding an end of strapping material, a powerdriven windlass for drawing the strapping material tight about an objectand a cutter for cutting the bound strap from the supply of strappingwith a single operating lever effective to operate the cutter,discontinue the application of power to the windlass and release thegripping means.

Other objects, features and advantages of the invention wiil becomeapparent as the description of a preferred embodiment thereof proceeds.

Referring now to the drawings:

FIG. l is a front elevational view of the tool showing the same in use;

FIG. 2 is a side elevational view of the tool;

FG. 3 is a plan view of the front portion of the tool, part of theoperating handle being broken away for clarity of illustration;

FlG. 4 is a `front elevational View showing the strap end gripping meansreleased and the cutter operated; and

FlG. 5 is an exploded View showing the construction of the strap endgripping means.

Patented June l5, i965 "ice In general the tool of the present inventionis similar to that described in the application of M. O. Derrickson,Serial No. 152,590, tiled November l5, 1961, now Patent No. 3,006,706and includes a more or less cylindrical handle portion l@ within whichis mounted a motor, preferably an air motor, operatively arranged todrive a strap tensioning means in the form of a slotted windlass lllwhich protrudes from the front end of the tool. The motor is driven froma source of compresssed air which is connected to the rear end of thehandle portion through a coupling l2. A valve for controlling the ilowof air to the motor has a stem i3 which extends outwardly from the sideof handle portion lil and said stem is provided with a finger piece 14by means of which it may be pushed into the handle portion against theaction of a spring to thereby admit compressed air to the motor andcause the same to drive windlass ll as explained in the above mentionedDerrickson application. An operating lever in the form of a bail l5having legs 16 and ll7vis pivotably mounted on the main body of thetool, the pivot for the leg lo being indicated in FIG. 2 at 31S.Extending outwardly from lthe lower end of leg 17 is a tab .t9 providedwith a cam slot 20, see FlG. 4, within which is engaged a pin 2l securedto an arm 22 of a cutter shaft 23. Cutter shaft 23 is rockably mountedin a member Z4 secured to the lower portion of a housing member 25 whichis iixed to the forward end of cylindrical handle portion lil. Member 24is provided with a strap-guiding slot 25 through which the strap ispulled lduring the tensioning operation, as will presently be explained.Cutter shaft 23 is cylindrical except where it passes through guide slot25' and in that area it has a iiat :sunface 26 best seen in FIG. 4. Thestrap, in passing through slot 25, lies beneath the flat surface Z6 andwhen the cutter shaft is rocked from the position shown in FIG. l to theposition shown in FIG. 4, an edge of fiat surface 2d in cooperation withan edge 27 of slot 25 cuts the strap.

A coil spring 28 extends around cutter shaft 23 between arm 22 and acollar 29 secured to or formed integrally with member 24. Spring 28 issecured at one end to arm 22 and at the other end to collar 29 and,through pin and slot connection Ztl and 2l, urges leg lo of bail leveri5 against the side of the valve stem i3 as shown in FIG. 3. With leg loresting against valve stern 13, the cutter member is positioned as shownin FIG. l so that the strap may be passed freely through guide slot 25and beneath the flat surface 26 of the cutter member. Valve stem 13 isprovided with a notch 3) and when said valve stein is pushed in toactivate the motor of the tool, spring 28 moves leg .t6 into said notchto thereby hold the valve stem in and continue the motor in operation.This slight movement of leg t6 and the accompanying movement of thecutter shaft is insuflicient to appreciably change the location of datsurface 26 of the cutter and does not result in cutting the strap. Whenbail lever l5 is moved rearwardly from the full-line position shown inFlG. 2 to the dotted-line position, the engagement of pin 2l within slot2i) causes the cutter shaft to rock from the FlG. l position to the FIG.4 position to thereby cut the tape and this rearward movement'of thebail lever also frees the leg 16 from notch 30 of the valve stemwhereupon the valve stem is moved out by its spring to shut otf themotor, as explained in the aforementioned Derriclrson application.

Secured to the housing member 25 on the side opposite member 24 is abracket 3l, the construction of which is best shown in FlG. 5, whichincludes a 'toot portion 32 located in alignment with the bottom of saidhousing member. A link 33 is pivotably mounted upon a shaft 3d (see PIG.4) extending between a pair of side plates E and 36 of the bracket 31and at its lower end said link has rockably mounted therein a pin 37rotatably mounted upon which is a drum 38 having a concave surface.Loosely mounted on pin 37 by means of a pair of ears 40 and 41 which lieadjacent the sides of lever 33 is a gripper member indicated generallyat 42 having a foot portion 43 which extends parallel to the uppersurface of foot portion 32 of bracket 31. As indicated at 44 in FIG. 4,the bottom surface of foot portion 43 is serrated. When the parts areassembled, ear 40 is aligned with side plate 35 of bracket 31 and ear 41lies adjacent the inner surface of side plate 36 of said bracket.

Side plate 36 is provided with a pair of downwardly sloping slots 45 and46. Pin 37 is engaged in slot 45 and a pin 47 extending from grippermember 42 rides in the slot 46. Link 33 and ears 40 and 41 constitute atoggle joint which when bent at the knee raises foot portion 43 awayfrom foot portion 32, as shown in FIG. 4. The engagement of pins 37 and47 within slots 45 and 46 causes the serrated bottom surface of footportion 43 to remain parallel to the upper surface of foot portion 32 atall times so that as the toggle joint is straightened the entire bottomsurface tof foot portion 43 engages the strap at one time to thus avoidpossible damage to the strap which might be caused by foot portion 43engaging it at an angle. A coil spring 48, shown in FIGS. 2 and 3,surrounds shaft 34 and is anchored at one end to link 33 and at theother to the side plate 36 of bracket 31. Spring 48 urges foot portion43 toward foot portion 32 and normally holds them in light engagement.Together, foot 32 and gripper member 42 constitute a strap end holdingmeans.

Extending outward from the lower end of bail lever leg 16 is a curvedtab 49 having a sloping cam surface Sil interconnecting twosubstantially vertical surfaces 51 and 52. When bail lever 15 is innormal position, that is with leg 16 bearing against the cylindricalsurface of valve stem 13, the upper vertical surface 51 of tab 49 isaligned but tout of contact with a roller 53 mounted on toggle jointshaft 37 and this relative position of surface 51 and roller 53 alsoprevails when leg 16 is located within the notch 30 of the valve stern,that is, when the motor is in operation. Thus, unless the serratedsurface 44 of foot portion 43 is actually in contact with foot portion32, shaft 37 is free to move toward the main body of the tool to morenearly straighten the toggle joint comprising link 33 and ears 40 and41. Upon movement of bail lever 15 from the full-line position shown inFIG. 2 to the dotted-line position, sloping cam surface contacts roller53 to bend the toggle joint as shown in FlG. 4 to thereby D raise footportion 43 out of contact with foot portion 32.

With lever 15 in the rearmost position, roller 53 is just at the edge ofcam surface 50 and does not move onto vertical surface 52. Therefore,upon release of lever 15, spring 48 is effective to restore said leverand gripper member 42 to the positions shown in FlGS. 1, 2, and 3.

In use, the tool may be placed upon a horizontal surface of the articleto be strapped, such as box 55 shown in FIG. l. A length of strappingmaterial 56 is then withdrawn from a supply and led about the box. Theoperator depresses or moves rearward the bail handle 15 thereby raisinggripper member 42 out of contact with foot portion 32 and inserts theleading end portion of the strap between the foot portion 43 of thegripper member and the foot portion 32 in such manner that the extremeend of the strap extends forward oi' member 24, that portion of thestrap between the extreme end and the gripper lying beneath member 24 asshown. The bail handle is Ithen released so that the strap is pinchedlightly between the foot portions 32 and 43. The trailing portion of thestrap is then inserted into guide slot 25 of member 24 and a portion ofthe strap is directed about roller 38 and engaged with the tensioningmeans or windlass 11 as shown in FIG. l. Valve stem 13 is then pushed inby means of the finger piece 14 to start the motor as aforesaid to causewindlass 11 to rotate in a counterclockwise direction. As the strap iswound about the windlass to draw it tight about the package, it exerts aforce on roller 38 toward the left as viewed in FIG. 1 and this forcetends to straighten the toggle joint comprised of crank 33 and ears 4t?and 41 of the gripper element 42 to thereby increase the pressure offoot portion 43 against the strap. Thus, the greater the tension appliedto the strap by windlass 11, the greater the restraining force appliedagainst the free end of the strap. As explained in the above referred toDerrickson application, when the strap reaches a preselected tension,the motor stalls and rotation of the windlass ceases but the windlasscontinues to maintain the tension on the strap. The overlapping portionsof the strap are then secured together forwardly of member 24 as byapplying a suitable seal thereabout in a well-known manner. With thestrap thus secured tightly about the package, the operator again movesbail handle 15 rearwardly to thereby operate cutter 23, release valvestem 13, so as to disconnect the motor, and raise the gripper member 42,all as hereinabove described.

Because of the rather sharp bend of the strap as it passes about roller38, the tool of the present invention is primarily intended to use witha strap having a higher degree of flexibility than steel strapping andit is contemplated that its greatest utility will be found in connectionwith the heavy-duty weftless cord straps currently coming into vogue.

Having thus described the invention and pointed out the utility thereof,what is claimed is:

1. A strap tensioning tool comprising tensioning means for engaging atrailing portion of a strap and drawing it tight about a package inoverlapping relationship with the leading end of the strap, strap endholding means for holding the leading end of the strap stationary whilethe strap is drawn tight by the tensioning means, said holding meanscomprising a relatively stationary member for engaging one face of thestrap and a relatively movable member for engaging the other face of thestrap so as to squeeze the strap therebetween, said members havingparallel strap engaging surfaces, means for maintaining parallelismbetween said surfaces in all relative positions of said members, springmeans urging said relatively movable member toward said relativelystationary member, means for moving said relatively movable member awayfrom said relatively stationary member, and means connected to saidrelatively movable member adapted to be engaged by the strap betweensaid end holding means and said tensioning means to move said movablemember toward said relatively stationary member as the strap is drawntight by the tensioning means whereby the squeezing force of said endholding means is increased as the strap is drawn tighter.

2. A strap tensioning tool comprising a windlass for engaging a trailingportion of a strap and drawing it tight about a package in overlappingrelationship with the leading end of the strap, control means movable toa iirst position to connect said windlass to power source and springurged to a second position wherein the windlass is disconnected from thepower source, strap gripping means for holding the leading end of thestrap stationary while the strap is drawn tight by said windless, meansassociated with said strap gripping means adapted to be engaged by thestrap between said gripping means and said windlass to increase thegripping action of said gripping means as the strap is drawn tight, aswingably mounted lever movable in a irst direction to hold said controlmean in its said irst position and in a second direction to permit saidcontrol means to move to its said second position, and means operativelyconnecting said lever .to said strap gripping means whereby movement ofsaid lever in its said second direction is effective to release saidgripping means from enga gement with the strap.

3. A strap tensioning tool comprising a windlass for engaging a trailingportion of a strap and drawing it tight about a package in overlappingrelationship with the leading end ot the strap, control means movable toa rst position to connect said windlass to a power source and springurged to a second position wherein the windlass is disconnected from thepower source, strap end holding means for holding the leading end of thestrap stationary while the strap is drawn tight by said windlass, saidholding means comprising a relatively stationary member for engaging oneface of the strap and a relatively movable member for engaging the otherface or" tho strap so as to squeeze the strap therebetween, meansassociated with Said relatively movable member adapted to be engaged bythe strap between said end holding means and said windlass to move saidmovable member toward said relatively stationary member as the strap isdrawn tight whereby the squeezing force of said end holding means isincreased as the strap is drawn tighter, a swingably mounted levermovable in a rst direction to hold said control means in its said rstposition and in a second direction to permit said control means to moveto its said second position, and means operatively connecting said leverto the relatively movable member of said strap end holding means wherebymovement of said lever in its said second direction is effective to movesaid relatively movable member away from said relatively stationarymember.

d. A strap tensioning tool comprising a windless for engaging a trailingportion of a strap and drawing it tight about a package in overlappingrelationship with the leading end of the strap, control means movable toa first position to connect said windlass to a power source and springurged to a second position wherein the Windlass is disconnected from thepower source, strap end holding means for holding the leading end of thestrap stationary while the strap is drawn tight by said windlass, saidholding means comprising a relatively stationary member for engaging oneface of the strap and a relatively movable member for engaging the otherface of the strap so as to squeeze the strap therebetween, said membershaving parallel strap engaging surfaces, means for maintainingparallelism between said surfaces in all relative positions of saidmembers, spring means urging said relatively movable member toward saidrelatively stationary member, means associated with said relativelymovable member adapted to be engaged by the strap between said endholding means and said windlass to move said movable member toward saidrelatively stationary member as the strap is drawn tight whereby thesqueezing force of said end holding means is increased as the strap isdrawn tighter, a swingably mounted lever movable in a iirst direction tohold said control means in its said irst position and in a seconddirection to permit said control means to move to its said secondposition, and means operatively connecting said lever to relativelymovable member of said strap end holding means whereby movement of saidlever in its said second direction is effective to move said relativelymovable member away from said relatively stationary member.

5. A strap tensioning tool comprising tensioning means for engaging atrailing portion of a strap and drawing it tight about a package inoverlapping relationship with the leading end of the strap, strap endholding means for holding the leading end of the strap stationary whilethe strap is drawn tight by the tensioning means, said holding meanscomprising a relatively stationary member for engaging one face or thestrap and a relatively movable member for engaging the other face of thestrap so as to squeeze the strap therebetween, a link pivotally mountedat one end on a stationary pivot, a pin pivotally connecting the otherend of said link to said relatively movable member, said link and saidrelatively movable member constituting a toggle joint, means associatedwith the toggle joint adapted to be engaged by the strap between thestrap end holding means and the tensioning means whereby increasingtension on the strap tends to straighten said toggle joint and cause therelatively movable member to move toward the relatively stationarymember whereby the squeezing *force of said end holding means isincreased as the strap is drawn tighter, and means for moving said pinto break the toggle joint and release the strap.

6. A strap tensioning tool comprising tensioning means or engaging atrailing portion of a strap and drawing it about a package inoverlapping relationship with the -ading end of the strap, strap endholding means for olding the leading end of the strap stationary whilethe strap is drawn tight by the tensioning means, said holding :leanscomprising a relatively stationary member for enone face of the strapand a relatively movable member for engaging the other face of the strapso las to squeeze the strap therebetween, said members having parallelstrap engaging surfaces, means for maintaining parallelism between saidsurfaces in all relative positions oi said members, a link pivotallymounted at one end on a stationary pivot, a pin pivotally connecting theother end ot said link to said relatively movable member, said link andsaid relatively movable member constituting a toggle joint, means onsaid pin adapted to be engaged by the strap between the strap endholding means and the tensioning means whereby increasing tension on thestrap tends to straighten said toggle joint and cause the strap engagingsurface of said relatively movable member to move toward the strapengaging surface of said relatively stationary member whereby thesqueezing force of said end holding means is increased as the strap isdrawn tighter, and means for moving said pin to bneak the toggle jointand release the strap.

'7. A strap tensioning tool comprising a windlass for engaging atrailing portion of a strap and drawing it tight about a package inoverlapping relationship with the leading end of the strap, controlmeans movable to a first position to connect said windlass to a powersource and spring urged to a second position wherein the windlass isdisconnected from the power source, strap end holding means for holdingthe leading end of the strap stationary while the strap is drawn tightby the tensioning means, said holding means comprising a relativelystationary member for engaging one face of the strap and a relativelymovable member for engaging the other face of the strap so as to squeezethe strap therebetween, said members having parallel strap engagingsurfaces, means for maintaining parallelism between said surfaces in allrelative positions of said members, a link pivotally mounted at one endon a stationary pivot, a pin pivotally connecting the other end oi saidlink to said relatively movable member, said link and said relativelymovable member constituting a toggle joint, means on said pin adapted tobe engaged by the strap between the strap end holding means and thetensioning means whereby increasing tension on the strap tends tostraighten said toggle joint and cause the strap engaging surface ofsaid relatively movable member to move toward the strap engaging surfaceof said relatively stationary member whereby the squeezing torce of saidend holding means is increased as the strap is drawn tighter, aswingable mounted lever movable in a iirst direction to hold saidcontrol means in its said irst position and in a second direction topermit said control means to move to its second position, said leverbeing ellective when moved in its second direction to engage said pinand break the toggle whereby the strap is `released from said endholding means.

References Cited by the Examiner UNITED STATES PATENTS 1,963,593 6/34Prindle 14C-93.4 2,580,848 l/52 Schulze 140-93 2,779,356 1/57 Schulze140-93 3,048,204 8/62 Lingle P10-123.6 3,066,706 12/62 Derrickson140-123.6

CHARLES W. LANHAM, Primary Examiner.

RICHARD A. WAHL, Examiner.

1. A STRAP TENSIONING TOOL COMPRISING TENSIONING MEANS FOR ENGAGING ATRAILING PORTION OF A STRAP AND DRAWING IT TIGHT ABOUT A PACKAGE INOVERLAPPING RELATIONSHIP WITH THE LEADING END OF THE STRAP, STRAP ENDHOLDING MEANS FOR HOLDING THE LEADING END OF THE STRAP STATIONARY WHILETHE STRAP IS DRAWN TIGHT BY THE TENSIONING MEANS, SAID HOLDING MEANSCOMPRISING A RELATIVELY STATIONARY MEMBER FOR ENGAGING ONE FACE OF THESTRAP AND A RELATIVELY MOVABLE MEMBER FOR ENGAGING THE OTHER FACE OF THESTAP SO AS TO SQUEEZE THE STAP THEREBETWEEN, SAID MEMBERS HAVINGPARALLEL STRAP ENGAGING SURFACES, MEANS FOR MAINTAINING PARALLELISMBETWEEN SAID SURFACES IN ALL RELATIVE POSITIONS OF SAID MEMBERS, SPRINGMEANS URGING SAID RELATIVELY MOVABLE MEMBER TOWARD SAID RELATIVELYSTATIONARY MEMBER, MEANS FOR MOVING SAID RELATIVELY MOVABLE MEMBERS AWAY